Go to homepageCyberStrike

Menu

Star on GitHub · 3.2k
Sign inDownload

CVE-2026-33753

6.2 · MEDIUM

rfc3161-client is a Python library implementing the Time-Stamp Protocol (TSP) described in RFC 3161.

Published Apr 8, 2026CWE-295EPSS 0.21%

Overview

CVE-2026-33753 is a medium-severity vulnerability. It was published on April 8, 2026 and has a CVSS 3.1 base score of 6.2 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.2, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical description

rfc3161-client is a Python library implementing the Time-Stamp Protocol (TSP) described in RFC 3161. Prior to 1.0.6, an Authorization Bypass vulnerability in rfc3161-client's signature verification allows any attacker to impersonate a trusted TimeStamping Authority (TSA). By exploiting a logic flaw in how the library extracts the leaf certificate from an unordered PKCS#7 bag of certificates, an attacker can append a spoofed certificate matching the target common_name and Extended Key Usage (EKU) requirements. This tricks the library into verifying these authorization rules against the forged certificate while validating the cryptographic signature against an actual trusted TSA (such as FreeTSA), thereby bypassing the intended TSA authorization pinning entirely. This vulnerability is fixed in 1.0.6.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/trailofbits/rfc3161-client/security/advisories/GHSA-3xxc-pwj6-jgrjGitHubgithub.com/trailofbits/rfc3161-client/security/advisories/GHSA-3xxc-pwj6-jgrj

How CyberStrike helps

Frequently asked questions

What is CVE-2026-33753?

CVE-2026-33753 is a medium-severity vulnerability. It was published on April 8, 2026 and has a CVSS 3.1 base score of 6.2 (MEDIUM).

How severe is CVE-2026-33753?

This vulnerability has a CVSS 3.1 base score of 6.2, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-33753?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-33753?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-33753 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

Related MEDIUM CVEs from 2026

View all
Browse by year2026202520242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999